Communication apparatus for transmitting trigger frames and receiving multiplexed data from a plurality of apparatuses

ABSTRACT

The present technology relates to a communication apparatus and a communication system achieving efficient utilization of a transfer path of a wireless LAN. A communication apparatus according to an aspect of the present technology transmits a first trigger frame containing a transmission parameter used for data transmission to a plurality of apparatuses belonging to a wireless LAN, and receives data multiplexed and transmitted from the plurality of apparatuses having received the first trigger frame in accordance with the transmission parameter. In addition, the communication apparatus receives a second trigger frame transmitted from a predetermined apparatus of the plurality of apparatuses, and transmits multiplexed data to the predetermined apparatus in accordance with a transmission parameter contained in the received second trigger frame. The present technology is applicable to a communication apparatus in a wireless LAN.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 16/982,160, filed on Sep. 18, 2020, which is a U.S.National Phase of International Patent Application No.PCT/JP2019/010148, filed on Mar. 13, 2019, which claims priority benefitof Japanese Patent Application No. JP 2018-059637 filed in the JapanPatent Office on Mar. 27, 2018. Each of the above-referencedapplications is hereby incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present technology relates to a communication apparatus and acommunication system, and particularly to a communication apparatus anda communication system achieving efficient utilization of a transferpath in a wireless LAN.

BACKGROUND ART

An access point of a wireless LAN is constituted by one communicationapparatus incorporating various functions. For example, a communicationapparatus operating as an access point has a modem function for managingaccess to the Internet, a function as a central control station forcontrolling communication in a wireless LAN, and a function for managinga communication apparatus connected to the wireless LAN.

In recent years, not only transfer of downlink data from an access pointto a plurality of communication apparatuses by using multiuser MIMO(Multi-Input Multi-Output), but also transfer of uplink data by usingmultiuser MIMO has been put into practical use. In this case, the accesspoint transmits a parameter necessary for transfer timing control or thelike to each of the plurality of communication apparatuses using atrigger frame.

CITATION LIST Patent Literature

-   [PTL 1]-   JP 2017-103666A

SUMMARY Technical Problems

The number of communication apparatuses each operable as an accesspoint, such as a smartphone incorporating a function called tethering,is increasing.

In a case where one communication apparatus performs processing foruplink and downlink multiuser MIMO even in the presence of a pluralityof communication apparatuses each operable as an access point in thesame wireless LAN, not only concentration of loads on the onecommunication apparatus performing the processing, but also a drop ofutilization efficiency of a transfer path may be caused.

The present technology has been developed in consideration of theaforementioned circumstances, and aims at efficient utilization of atransfer path in a wireless LAN.

Solution to Problems

A communication apparatus according to a first aspect of the presenttechnology includes a communication control unit. The communicationcontrol unit transmits a first trigger frame containing a transmissionparameter used for data transmission to a plurality of apparatusesbelonging to a wireless LAN, and receives data multiplexed andtransmitted from the plurality of apparatuses having received the firsttrigger frame in accordance with the transmission parameter. Moreover,the communication control unit receives a second trigger frametransmitted from a predetermined apparatus of the plurality ofapparatuses, and transmits multiplexed data to the predeterminedapparatus in accordance with a transmission parameter contained in thereceived second trigger frame.

A communication apparatus according to a second aspect of the presenttechnology includes a communication control unit. The communicationcontrol unit receives a trigger frame transmitted from a first apparatusthat performs a function of access control associated with access to awireless LAN and including transmission of a beacon frame, the triggerframe containing a transmission parameter used for data transmission. Inaccordance with the transmission parameter contained in the receivedtrigger frame, the communication control unit multiplexes and transmitsdata addressed to the first apparatus, and data transmitted via thefirst apparatus as a relay, and addressed to a second apparatus thatperforms a function of a gateway of the wireless LAN for an externalnetwork.

According to the first aspect of the present technology, the firsttrigger frame containing the transmission parameter used for datatransmission is transmitted to the plurality of apparatuses belonging tothe wireless LAN, and the data multiplexed and transmitted from theplurality of apparatuses having received the first trigger frame inaccordance with the transmission parameter is received. Moreover, thesecond trigger frame transmitted from the predetermined apparatus of theplurality of apparatuses is received, and the multiplexed data istransmitted to the predetermined apparatus in accordance with thetransmission parameter contained in the received second trigger frame.

According to the second aspect of the present technology, the triggerframe transmitted from the first apparatus that performs the function ofaccess control associated with access to the wireless LAN and includingtransmission of the beacon frame is received. The trigger frame containsthe transmission parameter used for data transmission. Moreover, inaccordance with the transmission parameter contained in the receivedtrigger frame, the data addressed to the first apparatus, and the datatransmitted via the first apparatus as a relay, and addressed to thesecond apparatus that performs the function of the gateway of thewireless LAN for the external network are multiplexed and transmitted.

Advantageous Effect of Invention

According to the present technology, efficient utilization of a transferpath in a wireless LAN is achievable.

Note that advantageous effects to be produced are not limited to theadvantageous effect described herein, but may be any advantageouseffects described in the present disclosure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram depicting a configuration example of a network in aconventional wireless LAN system.

FIG. 2 is a diagram depicting a configuration example of a network witha distributed function of AP according to an embodiment of the presenttechnology.

FIG. 3 is a diagram depicting a flow example of uplink data transmittedfrom Near Station.

FIG. 4 is a diagram depicting a flow example of downlink data to NearStation.

FIG. 5 is a diagram depicting a flow example of uplink data transmittedfrom Far Station.

FIG. 6 is a diagram depicting a flow example of downlink data to FarStation.

FIG. 7 is a diagram depicting an example of a positional relationbetween communication apparatuses.

FIG. 8 is a sequence diagram explaining a series of operations fordetermining roles of communication apparatuses.

FIG. 9 is a diagram depicting a configuration example of Role AvailableInformation Element.

FIG. 10 is a diagram depicting a configuration example of Role SeparateInformation Element.

FIG. 11 is a sequence diagram explaining a flow of communication betweencommunication apparatuses.

FIG. 12 is a diagram depicting a configuration example of a frame formatused for data transmission and reception.

FIG. 13 is a block diagram depicting a configuration example of acommunication apparatus.

FIG. 14 is a block diagram depicting a function configuration example ofa wireless communication module.

FIG. 15 is a sequence diagram explaining a flow of communication notusing spatial multiplexing.

FIG. 16 is a sequence diagram explaining a flow of communication usingspatial multiplexing.

FIG. 17 is a diagram depicting a configuration example of a triggerframe.

FIG. 18 is a diagram depicting a configuration example of an HE NDPAnnouncement frame.

FIG. 19 is a flowchart explaining a process performed by AC.

FIG. 20 is a flowchart explaining the process performed by AC andcontinuing from FIG. 19 .

FIG. 21 is a flowchart explaining a process performed by IG.

FIG. 22 is a flowchart explaining the process performed by IG andcontinuing from FIG. 21 .

FIG. 23 is a flowchart explaining a process performed by Near Station.

FIG. 24 is a flowchart explaining a process performed by Far Station.

FIG. 25 is a block diagram depicting a configuration example of acomputer.

DESCRIPTION OF EMBODIMENT

An embodiment for practicing the present technology will be hereinafterdescribed. The description will be presented in a following order.

1. Conventional network configuration example

2. Network configuration example according to one embodiment of presenttechnology

3. Operation example for constituting network with shared AP function

4. Configuration example of communication apparatus

5. Operation example of overall network

6. Operations of respective communication apparatuses

7. Modifications

<Conventional Network Configuration Example>

FIG. 1 is a diagram depicting a conventional network configurationexample of a wireless LAN.

A configuration depicted in FIG. 1 is a configuration where all controlof a network is performed by one communication apparatus. Stations 1 to6 are located within a radio wave reach range of an access point (AccessPoint) which is a communication apparatus performing all control of thenetwork. Each of small seven circles depicted in FIG. 1 indicates acommunication apparatus which has a function of wireless LANcommunication in conformity with predetermined specifications ofIEEE802.11, for example.

Station is a communication apparatus which operates as a communicationterminal belonging to a network managed by Access Point to become aclient. BSS (Basic Service Set) is constituted by Access Point andStation.

A circle #0 indicated by a broken line represents a communicable rangeof Access Point, that is, a radio wave reach range. For example, therange represented by the circle #0 is a radio wave reach rangecorresponding to use of allowable maximum transmission power.

In addition, circles #1 to #6 each indicated by a broken line representradio wave reach ranges of Stations 1 to 6, respectively. Stations 1 to3 are located near Access Point, while Stations 4 to 6 are located farfrom Access Point.

As indicated by the circles #1 to #3 around Stations 1 to 3,respectively, each of Stations 1 to 3 located near Access Point iscapable of communicating with Access Point even with reducedtransmission power.

On the other hand, as indicated by the circles #4 to #6 around Stations4 to 6, respectively, each of Stations 4 to 6 located away from AccessPoint is communicable with Access Point only when radio waves with themaximum transmission power are used without reduction of transmissionpower.

As described above, radio wave transmission power is difficult to reducein communication between Access Point and Station located far fromAccess Point. In this case, signals reach the ranges indicated by thecircles #0 and #4 to #6. More specifically, in a case where Access Pointis located at an end of the network, signals reach an area out of arange containing all communication apparatuses (for example, the rangeof the circle #3).

Accordingly, in a case where the one communication apparatus performsall control of the network as Access Point, sufficient effects aredifficult to obtain depending the position of Access Point even underreduction control of radio wave transmission power by each of thecommunication apparatuses.

Access Point will be hereinafter referred to as AP where appropriate. Inaddition, Station will be referred to as STA.

<Network Configuration Example According to One Embodiment of PresentTechnology>

FIG. 2 is a diagram depicting a network configuration example with adistributed function of AP according to one embodiment of the presenttechnology.

According to the example in FIG. 2 , a communication apparatus locatednear a center of a network operates as Access Controller, while acommunication apparatus located at an upper left position andconnectable with an external network such as the Internet operates asInternet Gateway.

Accordingly, in the example in FIG. 2 , the communication apparatusoperating as Access Controller performs a function of network accesscontrol including transmission of a management frame in a conventionalfunction of AP. The management frame transmitted by Access Controllerincludes a beacon frame, an action frame, a management frame, and atrigger frame.

As described below, the beacon frame includes information such asaddresses of respective communication apparatuses constituting thenetwork. Access to Access Controller and Internet Gateway from therespective communication apparatuses is controlled by signalstransmitted from Access Controller to specify a range of the network.

In addition, the communication apparatus operating as Internet Gatewayperforms a gateway function for the external network in the conventionalfunction of AP.

In the configuration where the communication apparatus different fromthe communication apparatus operating as Access Controller operates asInternet Gateway, STA belonging to the network is allowed to performnecessary communication such as communication via the Internet. Forexample, Internet Gateway communicates with a server managed by aservice provider which provides connection services for connection withthe Internet to control transmission and reception of uplink data anddownlink data.

Uplink data is data given from STA belonging to the network to InternetGateway or external apparatuses. Downlink data is data given fromInternet Gateway or external apparatuses to STA belonging to thenetwork.

As described above, the function of AP is shared by a plurality ofcommunication apparatuses. Accordingly, more efficient management of thenetwork is achievable. The function of AP includes at least a functionof network access control including transmission of the beacon frame anda function of a gateway for an external network.

In addition, radio waves are only required to reach a range aroundAccess Controller. Accordingly, each of the communication apparatuses isallowed to reduce radio wave transmission power.

For example, Access Controller is capable of transmitting signals suchas the beacon frame to a range indicated by a circle #11 containing allthe communication apparatuses even when radio wave transmission power isreduced.

Moreover, each of Internet Gateway and STA 1 to STA 5 is capable ofcommunicating with Access Controller using radio waves with minimumnecessary transmission power. A circle #12 represents a radio wave reachrange of Internet Gateway, while circles #21 to #25 represent radio wavereach ranges of STA 1 to STA 5, respectively.

The radio wave reach range of each of the communication apparatuses isset to a range narrower than the range of the circle #0 in FIG. 1 , forexample, which contains the positions of the adjacent communicationapparatuses. In other words, construction of a wireless LAN network isallowed in a narrow range around Access Controller.

Access Controller will be hereinafter referred to as AC whereappropriate. In addition, Internet Gateway will be referred to as IG.

In the network in FIG. 2 constructed in such a narrow range, each of STA1 and STA 2 located within a radio wave reach range of IG and capable ofdirectly communicating with IG operates as Near Station.

In addition, each of STA 3 to STA 5 is a communication apparatusincapable of directly communicating with IG but located in a radio wavereach range of AC operates as Far Station.

Operation as Near Station or operation as Far Station is specified onthe basis of a positional relation with IG.

FIG. 3 is a diagram depicting a flow example of uplink data transmittedfrom Near Station.

As indicated by a white arrow A1, uplink data to be transmitted from STA1 as Near Station to an external apparatus is directly received by IG,and then transmitted from IG to the external apparatus corresponding toa transmission destination. The external apparatus is an apparatusconnected to a network outside the network depicted in FIG. 3 , such asan apparatus in the Internet.

In addition, as indicated by a white arrow A2, uplink data to betransmitted from STA 2 to an external apparatus is directly received byIG, and then transmitted from IG to the external apparatus correspondingto a transmission destination.

FIG. 4 is a diagram depicting a flow example of downlink data to NearStation.

As indicated by a white arrow A11, downlink data transmitted from anexternal apparatus and received by IG as data to be transmitted to STA 1is directly transmitted from IG to STA 1. In addition, as indicated by awhite arrow A12, downlink data transmitted from an external apparatusand received by IG as data to be transmitted to STA 2 is directlytransmitted from IG to STA 2.

In such a manner, each of STA 1 and STA 2 operating as Near Station islocated in the radio wave reach range of IG and capable of directlycommunicating with IG.

FIG. 5 is a diagram depicting a flow example of uplink data transmittedfrom Far Station.

As indicated by white arrows A21 and A22, uplink data to be transmittedfrom STA 3 as Far Station to an external apparatus is received by IG viaAC as a relay, and then transmitted from IG to the external apparatuscorresponding to a transmission destination.

In addition, as indicated by white arrows A23 and A24 and white arrowsA25 and A26, each uplink data to be transmitted from STA 4 and STA 5 toan external apparatus is received by IG via AC as a relay, and thentransmitted from IG to the external apparatus corresponding to atransmission destination.

FIG. 6 is a diagram depicting a flow example of downlink data to FarStation.

As indicated by white arrows A31 and A32, downlink data transmitted froman external apparatus and received by IG as data to be transmitted toSTA 3 is transmitted from IG to STA 3 via AC as a relay.

In addition, as indicated by white arrows A33 and A34 and white arrowsA35 and A36, each downlink data transmitted from an external apparatusand received by IG as data to be transmitted to STA 4 and STA 5 istransmitted from IG to STA 4 and STA 5 via AC as a relay.

In such a manner, each of STA 3, STA 4, and STA 5 each operating as FarStation is located in the radio wave reach range of AC, and therefore iscapable of communicating with IG via AC as a relay.

In the network where the function of AP is shared by a plurality ofcommunication apparatuses, transmission and reception of uplink/downlinkdata are performed in the manner described above.

Accordingly, in the configuration where the communication apparatusoperable as AC and located at an optimum position performs a part of theconventional function of AP, an efficient network can be constructed ina necessary and sufficient range desired by a user.

More specifically, communication between the respective communicationapparatuses is efficiently performed in the manner described above bydesignating the communication apparatus located near the center of therange desired by the user as an apparatus performing the function of AC.

Moreover, in the configuration where the communication apparatusoperable as IG performs a part of the conventional function of AP, anoperation optimized for access to the Internet network is achievable bythis communication apparatus.

<Operation Example for Constituting Network with Shared AP Function>

Described here will be an operation of a network where the function ofAP is shared by a plurality of communication apparatuses in the mannerdescribed above.

It is assumed in the following description that STA 1 to STA 4 arearranged in this order from the left as depicted in FIG. 7 . Circles #51to #54 represent radio wave reach ranges of STA 1 to STA 4,respectively.

According to this example, each STA is capable of directly communicatingwith the second station away, but is uncapable of communicating with STAlocated farther. More specifically, STA 1 and STA 4 are unable tocommunicate with each other.

Each STA capable of performing the function of AP can exchangeinformation with surrounding STA using an action frame or the likecontaining information which indicates a function allowed to beperformed by corresponding STA.

Initially described with reference to a sequence in FIG. 8 will be aseries of operations for distributing the function of AP and determiningroles of respective STAs. While an operation using an action frame and abeacon frame is described here for convenience, a management frame maybe used instead of these frames.

Suppose here that STA 2 operable as AC is designated as a stationoperating as AC by the user. For example, designation of operation as ACis achieved by manipulating STA 2.

In a case where STA 2 is designated as the station operating as AC, STA2 transmits an action frame containing Role Available InformationElement in step S11. Information indicating own operability as AC isdescribed in Role Available Information Element contained in the actionframe transmitted by STA 2.

The action frame transmitted from STA 2 is received by STA 1 in step S1,and received by STA 3 in step S21. In addition, the action frametransmitted from STA 2 is received by STA 4 in step S31.

Suppose that STA 1, for example, in STAs having received the actionframe transmitted from STA 2 is a communication apparatus capable ofconnecting to the Internet.

In this case, STA 1 transmits an action frame containing Role AvailableInformation Element in step S2. Information indicating own operabilityas IG is described in Role Available Information Element contained inthe action frame transmitted by STA 1.

The action frame transmitted from STA 1 is received by STA 2 in stepS12, and received by STA 3 in step S22. STA 1 and STA 4 are unable todirectly communicate with each other. Accordingly, the action frametransmitted from STA 1 does not reach STA 4.

STA 2 operating as AC determines that the network with the distributedfunction of AP is manageable on the basis of reception of the actionframe transmitted from STA 1 operating as IG.

In step S13, STA 2 transmits a beacon frame containing Role SeparateInformation Element. Information indicating roles performed byrespective STAs is described in Role Separate Information Elementcontained in the beacon frame transmitted from STA 2.

STA 2 having transmitted the beacon frame implements setting foroperating as AC in step S14.

The beacon frame transmitted from STA 2 is received by STA 1 in step S3,and received by STA 3 in step S23. In addition, the beacon frametransmitted from STA 2 is received by STA 4 in step S32.

STA 1 having received the beacon frame transmitted from STA 2 in step S3implements setting for operating as IG in step S4.

On the other hand, STA 3 having received the beacon frame transmittedfrom STA 2 in step S23 is considered to have received both a signaltransmitted from STA 2 operating as AC and a signal transmitted from STA1 operating as IG with predetermined electric field intensity or higher.

In this case, STA 3 implements setting for operating as Near Station instep S24. STA 3 directly transmits and receives uplink/downlink data toand from IG.

In addition, STA 4 having received the beacon frame transmitted from STA2 in step S32 has received a signal transmitted from STA 2 operating asAC with predetermined electric field intensity or higher, but does notreceive a signal transmitted from STA 1 operating as IG.

STA 4 is located out of a direct reach range of a signal from STA 1.Accordingly, STA 4 implements setting for operating as Far Station instep S33. STA 4 transmits and receives uplink/downlink data via AC as arelay.

FIG. 9 is a diagram depicting a configuration example of Role AvailableInformation Element.

As depicted in FIG. 9 , Role Available Information Element contains IEType, Length, ESS ID, Own MAC Address, Controller Available, GatewayAvailable, and Intelligence Available.

IE type represents a format of an information element.

Length represents an information length of an information element.

ESS ID represents an identifier of an extension service set asnecessary.

Own MAC Address represents an own MAC address.

Controller Available is a flag indicating operability or non-operabilityas AC. According to the example in FIG. 8 , a setting value indicatingthat STA 2 is operable as AC is given to Controller Available of RoleAvailable Information Element contained in the action frame transmittedfrom STA 2.

Gateway Available is a flag indicating operability or non-operability asIG. According to the example in FIG. 8 , a setting value indicating thatSTA 1 is operable as IG is given to Gateway Available of Role AvailableInformation Element contained in the action frame transmitted from STA1.

Intelligence Available is a flag indicating operability ornon-operability as Intelligence Controller. A communication apparatusfunctioning as Intelligence Controller performs an authenticationprocess of the network and a process concerning association with thenetwork. More specifically, Intelligence Controller has a function forperforming an authentication function of the network and a function forprocessing a request for association with the network in theconventional function of AP.

In such a manner, the function of AP may be further subdivided todistribute a part of the function of AP to another communicationapparatus. In a case of distribution of the function of IntelligenceController, STA operable as Intelligence Controller transmits an actionframe containing Role Available Information Element which has a settingvalue indicating own operability as Intelligence Controller as a valueof Intelligence Available.

Each STA is capable of presenting a function allowed to be performed bycorresponding STA to another STA by using an action frame containing therespective items of information depicted in FIG. 9 . In addition, eachSTA is capable of checking the presence or absence of STA providing thefunction of AP performed by corresponding STA within the network towhich corresponding STA belongs on the basis of an action frametransmitted from another STA.

FIG. 10 is a diagram depicting a configuration example of Role SeparateInformation Element.

As depicted in FIG. 10 , Role Separate Information Element contains IEType, Length, SSID, ESS ID, Controller Address, Gateway Address, andIntelligence Address. IE Type, Length, and ESS ID are identical to IEType, Length, and ESS ID described with reference to FIG. 9 ,respectively. SSID is a service set identifier set as necessary.

Controller Address represents an address of STA operating as AC.

Gateway Address represents an address of STA operating as IG.

Intelligence Address represents an address of STA operating asIntelligence Controller.

According to the example in FIG. 8 , a setting of an own address of STA2 is given to Controller Address of Role Separate Information Elementcontained in a beacon frame transmitted from STA 2, while a setting ofan address of STA 1 is given to Gateway Address. For example, theaddress of STA 1 set as Gateway Address is specified at STA 2 on thebasis of Own MAC Address of Role Available Information Element of theaction frame transmitted from STA 1.

STA operating as AC is capable of presenting addresses of STAsperforming the function of AP to other STAs by using a beacon framecontaining respective items of information depicted in FIG. 10 . Inaddition, each of STAs is capable of specifying addresses of other STAsperforming the function of AP and belonging to the network to whichcorresponding STA belongs on the basis of a beacon frame transmittedfrom STA operating as AC.

A plurality of functions of AP may be performed by one STA. In thiscase, a setting of an address of identical STA is given to two or moreof Controller Address, Gateway Address, and Intelligence Address.

In addition, a plurality of addresses of IG may be described in RoleSeparate Information Element. In a case where a plurality of STAsoperable as IG is present in one network, a beacon frame containing RoleSeparate Information Element where the respective addresses aredescribed is transmitted from AC.

At the time of determination of roles of STAs, an action framecontaining Role Available Information Element as management informationand a beacon frame containing Role Separate Information Element asmanagement information as described above are transmitted and receivedbetween respective STAs.

A flow of communication between STAs will be described next withreference to a sequence in FIG. 11 .

It is assumed that STA 1, STA 2, STA 3, and STA 4 implement setting foroperating as IG, AC, Near Station, and Far Station, respectively, byperforming the processing described with reference to FIG. 8 .

As indicated by white arrows A51 and A52, respectively, data addressedto AC and data addressed to Near Station both transmitted from IG aredirectly transmitted to AC and Near Station, respectively, as DownlinkDirect Data.

On the other hand, as indicated by a white arrow A53, data addressed toFar Station and transmitted from IG is transmitted from IG to AC asDownlink Relay Data. Thereafter, as indicated by a white arrow A54, thisdata is transmitted to Far Station via AC as a relay. In FIG. 11 , abroken arrow located after the white arrow A53 indicates that datatransmitted from IG does not directly reach Far Station.

As indicated by white arrows A55 and A56, respectively, data addressedto AC and data addressed to IG both transmitted from Near Station aredirectly received by AC and IG, respectively, as Uplink Direct Data.

On the other hand, as indicated by a white arrow A57, data addressed toIG and transmitted from Far Station is received by AC as Uplink RelayData. Thereafter, as indicated by a white arrow A58, the data istransmitted to IG via AC as a relay.

FIG. 12 is a diagram depicting an example of a format of a data frameused for transmission and reception of data.

As depicted in FIG. 12 , a data frame includes MAC Header, Frame Body,and FCS.

MAC Header includes fields such as Frame Control, Duration, Address 1,Address 2, Address 3, Sequence Control, Address 4, QoS Control, and HEControl.

Control information and a format associated with a frame are describedin Frame Control.

Duration of the frame and duration for returning a response aredescribed in Duration.

Described in each of Address 1, Address 2, Address 3, and Address 4 isBSS ID or the like which indicates an address of STA corresponding to arelay or an address of an access point, as well as an address of STAcorresponding to a transmitter or an address of STA corresponding to areceiver at the time of execution of direct transfer.

A parameter associated with a sequence number or the like is describedin Sequence Control.

A parameter associated with QoS is described in QoS Control.

A parameter for performing efficient transfer is described in HEControl.

Frame Body contains data associated with a transmission target.

A parameter for detecting an error of MAC Header is described in FCS.

<Configuration Example of Communication Apparatus>

FIG. 13 is a block diagram depicting a configuration example of acommunication apparatus.

A communication apparatus 11 depicted in FIG. 13 is STA which operatesas AC, IG, IC (Intelligence Controller), Near Station, Far station, orthe like.

For example, the communication apparatus 11 includes an Internetconnection module 21, an information input module 22, a device controlunit 23, an information output module 24, and a wireless communicationmodule 25. Some parts in the configuration depicted in FIG. 13 may beeliminated as necessary depending on a function performed by thecorresponding communication apparatus 11.

In a case where the communication apparatus 11 operates as IG, theInternet connection module 21 functions as a communication modem forconnection to the Internet. More specifically, the Internet connectionmodule 21 outputs data received via the Internet to the device controlunit 23, and transmits data supplied from the device control unit 23 toan apparatus corresponding to a transmission destination via theInternet.

The information input module 22 detects a manipulation performed by theuser, and outputs information indicating contents of the manipulation bythe user to the device control unit 23. For example, in a case where abutton, a keyboard, a touch panel, or the like provided on a housing ofthe communication apparatus 11 is manipulated, the information inputmodule 22 outputs a signal corresponding to the manipulation performedby the user to the device control unit 23.

The device control unit 23 includes a CPU (Central Processing Unit), aROM (Read Only Memory), a RAM (Random Access Memory), and the like. Thedevice control unit 23 executes a predetermined program using the CPU,and controls an overall operation of the communication apparatus 11according to a signal or the like supplied from the information inputmodule 22.

For example, the device control unit 23 outputs downlink data suppliedfrom the Internet connection module 21 to the wireless communicationmodule 25, and causes the wireless communication module 25 to transmitthe data to a communication apparatus corresponding to a transmissiondestination. Moreover, the device control unit 23 acquires, from thewireless communication module 25, uplink data transmitted from acommunication apparatus belonging to the network and received by thewireless communication module 25, and outputs the uplink data to theInternet connection module 21. The device control unit 23 causes theinformation output module 24 to output predetermined information asnecessary.

The information output module 24 includes a display unit constituted bya liquid crystal panel or the like, a speaker, an LED (Light EmittingDiode), and the like. The information output module 24 outputs varioustypes of information such as information indicating an operation stateof the communication apparatus 11, and information acquired via theInternet on the basis of information supplied from the device controlunit 23 to present the information to the user.

The wireless communication module 25 is a wireless LAN module inconformity with predetermined specifications. For example, the wirelesscommunication module 25 is constituted by an LSI chip.

The wireless communication module 25 transmits data supplied from thedevice control unit 23 to another apparatus in the form of apredetermined format frame, and receives a signal transmitted fromanother apparatus to output data extracted from the received signal tothe device control unit 23.

FIG. 14 is a block diagram depicting a functional configuration exampleof the wireless communication module 25.

As depicted in FIG. 14 , the wireless communication module 25 includesan input/output unit 51, a communication control unit 52, and a basebandprocessing unit 53.

The input/output unit 51 includes an interface unit 101, a transmissionbuffer 102, a network management unit 103, a transmission frameconstruction unit 104, a reception data construction unit 115, and areception buffer 116.

The communication control unit 52 includes an access control unit 105, amanagement information generation unit 106, a transmission timingcontrol unit 107, a reception timing control unit 113, and a managementinformation processing unit 114.

The baseband processing unit 53 includes a transmission power controlunit 108, a wireless transmission processing unit 109, an antennacontrol unit 110, a wireless reception processing unit 111, and adetection threshold control unit 112.

The interface unit 101 of the input/output unit 51 functions as aninterface for exchanging data in a predetermined signal format with thedevice control unit 23 in FIG. 13 . For example, the interface unit 101outputs transmission target data supplied from the device control unit23 to the transmission buffer 102. In addition, the interface unit 101outputs reception data stored in the reception buffer 116 and receivedfrom the other communication apparatus 11 to the device control unit 23.

The transmission buffer 102 temporarily stores transmission target data.The transmission target data stored in the transmission buffer 102 isread by the transmission frame construction unit 104 at predeterminedtiming.

The network management unit 103 manages information indicating an ownfunction in the network. For example, in a case where the function to beperformed is AC, the network management unit 103 manages addresses ofthe communication apparatuses 11 constituting the network.

Moreover, the network management unit 103 manages functions performed bythe other communication apparatuses 11 belonging to the network, such asthe communication apparatus 11 operating as AC, and the communicationapparatus 11 operating as IG. The network is managed by the networkmanagement unit 103 on the basis of information supplied from theinterface unit 101 and the access control unit 105.

The network management unit 103 outputs various types of informationsuch as addresses to the respective units, i.e., the transmission frameconstruction unit 104, the access control unit 105, and the receptiondata construction unit 115, as necessary.

The transmission frame construction unit 104 generates a data frame usedfor transmitting data stored in the transmission buffer 102, and outputsthe generated data frame to the wireless transmission processing unit109.

The access control unit 105 of the communication control unit 52performs various types of control in accordance with the own functionmanaged by the network management unit 103. For example, in a case ofown operation as AC, the access control unit 105 outputs managementinformation, which is information to be stored in a management frame, tothe management information generation unit 106.

Moreover, the access control unit 105 performs access control inaccordance with a predetermined communication protocol on the basis ofinformation supplied from the network management unit 103 and themanagement information processing unit 114.

In a case of own operation as AC, the access control unit 105 controlstransmission of a null-data packet (NDP (Null Data Packet)), andtransmission of a trigger frame. In the network described above wherethe function of AP is distributed to a plurality of the communicationapparatuses 11, data transfer by multiuser MIMO is performed not onlybetween IG and the other communication apparatus 11, but also between ACand the other communication apparatus 11. The trigger frame is used fortransfer of parameters for transmission timing control and the like in acase of data transfer by multiuser MIMO.

The access control unit 105 of the communication apparatus 11 operatingas IG also controls transmission of a null-data packet, and transmissionof a trigger frame.

The management information generation unit 106 generates a managementframe containing management information supplied from the access controlunit 105, and outputs the generated management frame to the wirelesstransmission processing unit 109. The management frame generated by themanagement information generation unit 106 of the communicationapparatus 11 operating as AC contains an action frame, a beacon frame,and a trigger frame.

The transmission timing control unit 107 controls frame transmissiontiming of the wireless transmission processing unit 109. For example,the transmission timing is designated by the access control unit 105.

The transmission power control unit 108 of the baseband processing unit53 controls radio wave transmission power in accordance with control bythe access control unit 105 and the transmission timing control unit107.

For example, radio wave transmission power of the communicationapparatus 11 operating as AC is set within a level sufficient for directcommunication with all of the communication apparatuses 11 belonging tothe network, including IG. In addition, radio wave transmission power ofeach of the communication apparatuses 11 performing functions other thanAC is set within a level sufficient for direct communication with atleast AC.

The wireless transmission processing unit 109 converts the data framegenerated by the transmission frame construction unit 104 and themanagement frame generated by the management information generation unit106 into a baseband signal. Moreover, the wireless transmissionprocessing unit 109 performs various types of signal processing such asmodulation processing for the baseband signal, and supplies the basebandsignal subjected to the signal processing to the antenna control unit110.

The antenna control unit 110 is constituted by connection of a pluralityof antennas including antennas 25A and 25B. The antenna control unit 110transmits, from the antennas 25A and 25B, the signal supplied from thewireless transmission processing unit 109. Moreover, the antenna controlunit 110 outputs, to the wireless reception processing unit 111, thesignal supplied from the antennas 25A and 25B in response to receptionof radio waves transmitted from another apparatus.

The wireless reception processing unit 111 detects a preamble of a frametransmitted in a predetermined format from the signal supplied from theantenna control unit 110, and receives data constituting a header and adata portion and continuing from the preamble. The wireless receptionprocessing unit 111 outputs data contained in a management frame such asa beacon frame and a trigger frame to the management informationprocessing unit 114, and outputs data contained in a data frametransmitted from the other communication apparatus 11 to the receptiondata construction unit 115.

The detection threshold control unit 112 inputs, to the wirelessreception processing unit 111, a setting of a threshold which is areference for detection of a signal such as a preamble. For example, ina state where radio wave transmission power of the network iscontrolled, the threshold is set by the detection threshold control unit112 in accordance with control by the access control unit 105.

The reception timing control unit 113 of the communication control unit52 controls frame reception timing of the wireless reception processingunit 111. For example, the reception timing is designated by the accesscontrol unit 105. Information associated with the frame reception timingis supplied to the transmission timing control unit 107 as necessary.

The management information processing unit 114 analyzes a managementframe constituted by data and supplied from the wireless receptionprocessing unit 111. In a case of own designation as a transmissiondestination of the management frame, the management informationprocessing unit 114 extracts a parameter stored in the management frameto analyze contents of the parameter. The management informationprocessing unit 114 outputs information indicating an analysis result tothe access control unit 105 and the reception data construction unit115. The management information processing unit 114 also analyzes a nulldata packet as necessary.

The reception data construction unit 115 of the input/output unit 51removes a header from a data frame constituted by data supplied from thewireless reception processing unit 111 to extract a data portion. Thereception data construction unit 115 outputs data contained in theextracted data portion to the reception buffer 116 as reception data.The reception data output to the reception buffer 116 is data addressedto the own address.

The reception buffer 116 temporarily stores the reception data suppliedfrom the reception data construction unit 115. The reception data storedin the reception buffer 116 is read by the interface unit 101 atpredetermined timing, and output to the device control unit 23.

The wireless communication module 25 includes the input/output unit 51,the communication control unit 52, and the baseband processing unit 53each including the above units. In a case where the function of AP isshared by a plurality of the communication apparatuses 11, operations ofthe respective units are switched depending on the function performed byeach of the communication apparatuses 11.

<Operation Example of Overall Network>

Example not Using Spatial Multiplexing

A flow of communication between the communication apparatuses 11configured as above will be described here with reference to a sequencein FIG. 15 .

The flow of communication depicted in FIG. 15 is basically similar tothe flow of communication described with reference to FIG. 11 . It isassumed that settings for operating as IG, AC, Near Station, and FarStation are input to STA 1 to STA 4 as the four communicationapparatuses 11, respectively. Operations of IG, AC, Near Station, andFar Station are depicted in this order from the top. Each of Horizontalaxes in FIG. 15 represents time.

The respective communication apparatuses 11 in the example of FIG. 15have the same positional relation as that of FIG. 7 . That is, each ofthe communication apparatuses 11 is capable of directly communicatingwith the second communication apparatus 11 away, but is uncapable ofcommunicating with the communication apparatus 11 located farther. Morespecifically, STA 1 operating as IG and STA 4 operating as Far Stationare unable to communicate with each other.

It is assumed that an access right (right for transmitting data) isequitably given to all the communication apparatuses in the example ofFIG. 15 . While one of the communication apparatuses 11 is transmittingdata in this configuration, the other communication apparatuses 11perform control for suspending data transmission.

As depicted in the left end in the uppermost stage, IG transmits data toAC and Near Station as Downlink (DL) Direct Data in a case of datatransmission from IG to AC and Near Station as indicated by white arrowsA71 and A72.

Concerning data addressed to Far Station, however, IG needs to requestAC to function as a relay. In a case of data transmission to FarStation, IG transmits data to AC as Downlink Relay Data as indicated bya white arrow A73.

As depicted in the second stage, AC is capable of communicating with allof the communication apparatuses 11. In a case of data transmission fromAC to IG, AC transmits data to IG as Uplink (UL) Direct Data asindicated by a white arrow A74.

In a case of data transmission from AC to Near Station and Far Station,AC transmits data to Near Station and Far Station as Downlink DirectData as indicated by white arrows A75 and A76.

Moreover, AC relays data transmitted from IG and addressed to FarStation, and transmits the data to Far Station as Downlink Relay Data asindicated by a white arrow A77.

As depicted in the third stage, in a case of data transmission from NearStation to IG and AC, Near Station transmits data to IG and AC as UplinkDirect Data as indicated by white arrows A78 and A79.

As depicted in the fourth stage, in a case of data transmission from FarStation to AC, Far Station transmits data to AC as Uplink Direct Data asindicated by a white arrow A80.

Concerning data addressed to IG, however, Far Station needs to requestAC to function as a relay. In a case of data transmission from FarStation to IG, Far Station transmits data to AC as Uplink Relay Data asindicated by a white arrow A81.

AC relays data transmitted from Far Station and addressed to IG, andtransmits the data to IG as Uplink Relay Data as indicated by a whitearrow A82.

In such a manner, data transmission is achievable such that only one ofthe communication apparatuses 11 transmits data at certain timing.

Example Using Spatial Multiplexing

Another flow of communication between the communication apparatuses 11will be described with reference to a sequence in FIG. 16 . Descriptionsimilar to the description given with reference to FIG. 15 will beomitted where appropriate.

FIG. 16 depicts a flow of communication in a case where data transfer isperformed using multiuser MIMO. Multiuser MIMO is a method whichspatially multiplexes transmission data from a plurality of terminals tosimultaneously transfer the data to one terminal, for example.

Data transfer by multiuser MIMO is basically achieved by transmitting asounding request using a null data packet from a terminal on thereception side, and returning sounding using a null data packet to theterminal on the reception side from a terminal having received thesounding request. A terminal performing data transfer and the like arespecified at the terminal on the reception side on the basis of thereturned sounding. A trigger frame containing parameters specifyingtransmission timing and the like is transmitted from the terminal on thereception side to each terminal.

In the network described above where the function of AP is shared by aplurality of the communication apparatuses 11, multiuser MIMO is usedfor both data transfer to AC and data transfer to IG in the network. Inother words, data is transferred to each of the plurality ofcommunication apparatuses 11 designated as a data transmissiondestination using multiuser MIMO.

Multiuser MIMO used for data transfer to AC as a transmissiondestination in response to a trigger (cause) given from AC is herereferred to as uplink multiuser MIMO (UL MU) to AC. Multiuser MIMO usedfor data transmission from AC to the other communication apparatus 11 asa transmission destination is referred to as downlink multiuser MIMO (DLMU) from AC.

In addition, multiuser MIMO used for data transfer to IG as atransmission destination in response to a trigger (cause) given from IGis here referred to as uplink multiuser MIMO to IG. Multiuser MIMO usedfor data transmission from IG to the other communication apparatus 11 asa transmission destination is referred to as downlink multiuser MIMOfrom IG.

In a case of execution of uplink multiuser MIMO to AC, AC transmits asounding request (Q1) using a null data packet at a time t1 as indicatedat the left end in the second stage.

Each of IG, Near Station, and Far Station having received the soundingrequest (Q1) from AC returns sounding (S1) using a null data packet inresponse to the sounding request. At a time t2, AC receives the sounding(S1) returned from each of IG, Near Station, and Far Station.

Note that the sounding (S1) given in response to the sounding requestmay be returned substantially at the same time using OFDMA (orthogonalfrequency-division multiple access) technology, for example, instead ofindividually fed back to AC. A parameter indicating an amount of datatransmitted from each of IG, Near Station, and Far Station is includedin the sounding (S1) and transmitted to AC.

At a time t3, AC having received the sounding (S1) sets a transmissionparameter corresponding to the amount of data transmitted from each ofIG, Near Station, and Far Station, and transmits a trigger frame (T1)containing the transmission parameter. At a time t4, each of IG, NearStation, and Far Station designated by the trigger frame (T1) transmitsdata by uplink multiuser MIMO to AC in accordance with predeterminedprocedures.

For example, as indicated by a white arrow A101, IG multiplexes DownlinkDirect Data and Downlink Relay Data, and transmits the multiplexed data.In addition, as indicated by a white arrow A102, Near Station transmitsUplink Direct Data. As indicated by a hatched arrow A103, Far Stationmultiplexes Uplink Direct Data and Uplink Relay Data, and transmits themultiplexed data.

Respective pieces of data to AC are spatially multiplexed andtransmitted using multiuser MIMO. AC receives data simultaneouslytransmitted by multiuser MIMO.

Uplink multiuser MIMO to IG is performed in a similar manner.

More specifically, for performing uplink multiuser MIMO to IG, IGtransmits a sounding request (Q2) using a null data packet at a timet11.

Each of AC and Near Station having received the sounding request (Q2)from IG returns sounding (S2) using a null data packet in response tothe sounding request. At a time t12, IG receives the sounding (S2)returned from each of AC and Near Station. The sounding request (Q2)from IG does not reach Far Station. Accordingly, sounding is notreturned from Far Station.

The sounding (S2) corresponding to the sounding request from IG may bereturned using OFDMA similarly to the sounding (S1). A parameterindicating an amount of data to be transmitted from each of AC and NearStation is included in the sounding (S2) and transmitted to IG.

At a time t13, IG having received the sounding (S2) sets a transmissionparameter corresponding to the amount of data transmitted from each ofAC and Near Station, and transmits a trigger frame (T2) containing thetransmission parameter.

At a time t14, each of AC and Near Station designated by the triggerframe (T2) transmits data by uplink multiuser MIMO to IG in accordancewith predetermined procedures.

For example, as indicated by a white arrow A104, AC multiplexes UplinkDirect Data and Uplink Relay Data, and transmits the multiplexed data.The Uplink Relay Data transmitted here is data transmitted from FarStation by uplink multiuser MIMO to AC. In addition, as indicated by ahatched white arrow A105, Near Station transmits Uplink Direct Data.

Respective pieces of data to IG are spatially multiplexed andtransmitted using multiuser MIMO. IG receives the data simultaneouslytransmitted by multiuser MIMO.

As described above, in the network where the function of AP is shared bya plurality of the communication apparatuses 11, data is allowed to betransferred by multiuser MIMO in response to triggers from AC and IG.

On the other hand, for performing downlink multiuser MIMO from AC, ACmultiplexes Downlink Direct Data to Near Station, and Downlink DirectData and Downlink Relay Data to Far Station, and transmits themultiplexed data at a time t21 as indicated by a white arrow A106 and anarrow A107. Downlink Relay Data transmitted here is data transmittedfrom IG by uplink multiuser MIMO to AC. Note that Uplink Direct Data andUplink Relay Data to IG may be multiplexed and transmitted as foregoingdownlink multiuser MIMO from AC described above as necessary asindicated by an arrow A108.

Timing of downlink multiuser MIMO from AC is an occasion that ACacquires a predetermined access right, or is designated by a parametercontained in the trigger frame (T1), for example. Note that theparameter used for downlink data transfer may be a parameter having beenexchangeable at the time of uplink data transfer.

Near Station receives Downlink Direct Data transmitted by downlinkmultiuser MIMO from AC. Moreover, Far Station receives Downlink DirectData and Downlink Relay Data transmitted from AC by downlink multiuserMIMO from AC.

For performing downlink multiuser MIMO from IG, IG multiplexes DownlinkDirect Data to AC, and Downlink Direct Data to Near Station, andtransmits the multiplexed data at a time t22 as indicated by a whitearrow A109 and an arrow A110. Timing of downlink multiuser MIMO from IGis an occasion that IG acquires a predetermined access right, or isdesignated by a parameter contained in the trigger frame (T2), forexample.

AC receives Downlink Direct Data transmitted by downlink multiuser MIMOfrom IG. Near Station receives Downlink Direct Data transmitted bydownlink multiuser MIMO from IG.

As described above, in the network where the function of AP is shared bya plurality of the communication apparatuses 11, both AC and IG areallowed to perform, by using multiuser MIMO, downlink data transfer inaddition to uplink data transfer.

Efficient use of a transfer path of a wireless LAN is achievable byallowing data transfer using multiuser MIMO in response to triggers froma plurality of the communication apparatuses 11.

For example, in the data transfer described with reference to FIG. 15 ,transmission timing of Downlink Direct Data and transmission timing ofDownlink Relay Data from IG to AC are different from each other.However, these pieces of data are simultaneously transmitted in theexample of FIG. 16 . In addition, in the data transfer described withreference to FIG. 15 , transmission timing of Downlink Direct Data andtransmission timing of Downlink Relay Data from AC to Far Station aredifferent from each other. However, these pieces of data aresimultaneously transmitted in the example of FIG. 16 .

Efficient use of a transfer path is achievable by simultaneoustransmission of data relayed by AC and other data.

According to the example of FIG. 16 , respective pieces of data aresuccessively transmitted. However, these respective pieces of data maybe transmitted on an occasion that the communication apparatus 11transmitting data acquires an access right to a transfer path. Forexample, transmission timing may be set for respective pieces of dataaccording to an access category of data under enhanced distributionchannel access (EDCA) control.

FIG. 17 is a diagram depicting a configuration example of a triggerframe.

As depicted in FIG. 17 , the trigger frame includes Padding and FCS inaddition to Frame Control, Duration, RA (Receiver Address), TA(Transmitter Address), Common Info, and User Info 1 to N.

Frame Control is information for specifying a frame type.

Duration represents frame duration.

RA represents an address of STA corresponding to a receiver of thetrigger frame. TA represents an address of STA corresponding to atransmitter of the trigger frame. Common Info is information common torespective STAs.

Each of User Info 1 to N is individual user information. A transmissionparameter used by each of the communication apparatuses 11 for datatransmission, such as a parameter indicating transmission timing, isdescribed as User Info 1 to N.

An address of any of the communication apparatuses 11 as the apparatustriggering data transfer by multiuser MIMO is described in a field ofthe trigger frame TA having the respective items of informationdescribed above.

More specifically, an address of the communication apparatus 11operating as AC is described in the trigger frame TA transmitted by AC.In addition, an address of the communication apparatus 11 operating asIG is described in the trigger frame TA transmitted by IG.

The communication apparatus 11 having received the trigger frame iscapable of specifying, on the basis of the description of TA, which ofAC and IG is the function performed by the communication apparatus 11having transmitted the trigger frame.

FIG. 18 is a diagram depicting a configuration example of an HE NDP(High Efficiency Null Data Packet) Announcement frame.

The HE NDP Announcement frame is a management frame transmitted as asounding request using a null data packet. A format and the like of thenull data packet (NDP) are designated on the basis of informationcontained in the HE NDP Announcement frame.

As depicted in FIG. 18 , the HE NDP Announcement frame includes FCS inaddition to Frame Control, Duration, RA, TA, Sounding Dialog Token, andSTA Info 1 to N.

Frame Control is information for specifying a frame type.

Duration represents frame duration.

RA represents an address of STA corresponding to a receiver of the HENDP Announcement frame.

TA represents an address of STA corresponding to a transmitter of the HENDP Announcement frame.

Sounding Dialog Token represents a parameter associated with sounding.

Each of STA Info 1 to N is individual STA information.

An address of any of the communication apparatuses 11 as the apparatusissuing a sounding request is described in a field of TA of the HE NDPAnnouncement frame containing the respective items of informationdescribed above.

More specifically, an address of the communication apparatus 11operating as AC is described in TA of the HE NDP Announcement frametransmitted by AC. In addition, an address of the communicationapparatus 11 operating as IG is described in TA of the HE NDPAnnouncement frame transmitted by IG.

The communication apparatus 11 having received the HE NDP Announcementframe is capable of specifying, on the basis of the description of TA,which of AC and IG is the function performed by the communicationapparatus 11 having transmitted the HE NDP Announcement frame.

<Operations of Respective Communication Apparatuses>

Next described will be an operation of each of the communicationapparatuses 11 which perform data transfer using multiuser MIMO.

Operation of AC

Processing performed by AC will be initially described with reference toa flowchart in FIGS. 19 and 20 .

In step S101, the device control unit 23 of AC (FIG. 13 ) acquires ownrole information. For example, the role information which is informationindicating the own role (function) is set after roles are distributed bythe processing described with reference to FIG. 8 , and stored in amemory constituting the device control unit 23.

In step S102, the device control unit 23 determines operation ornon-operation as AC.

In a case where operation as AC is determined in step S102, theinterface unit 101 determines whether or not transmission data has beensupplied in step S103. For example, in a case where the device controlunit 23 transmits data generated by an executed application to the othercommunication apparatus 11, transmission data is supplied to theinterface unit 101 from the device control unit 23.

In a case of determination that transmission data has been supplied instep S103, the interface unit 101 outputs the transmission data suppliedfrom the device control unit 23 to the transmission buffer 102, andcauses the transmission buffer 102 to store the transmission data asDirect Data in step S104. Data transmitted by AC is data directlytransmittable to all of the communication apparatuses 11. In a case ofdetermination that transmission data has not been supplied in step S103,processing in step S104 is skipped.

In step S105, the access control unit 105 determines whether or not thecurrent timing is beacon frame transmission timing.

In a case of determination that the current timing is beacon frametransmission timing in step S105, the access control unit 105 acquires aparameter, and causes the management information generation unit 106 togenerate a beacon frame containing the acquired parameter in step S106.

In step S107, the wireless transmission processing unit 109 transmitsthe beacon frame generated by the management information generation unit106. The beacon frame transmitted here contains Role SeparateInformation Element (FIG. 10 ) to which a setting of an own address asController Address, and a setting of an address of IG as Gateway Addressare input, for example. In a case of determination that the currenttiming is not beacon frame transmission timing in step S105, processingin steps S106 and S107 is skipped.

In step S108, the access control unit 105 determines whether or not thecurrent timing is timing for performing uplink multiuser MIMO to AC.

In a case of determination that the current timing is timing forperforming uplink multiuser MIMO to AC in step S108, the managementinformation generation unit 106 generates an HE NDP Announcement frame(FIG. 18 ) as an NDP notification frame, for example, and causes thewireless transmission processing unit 109 to transmit the HE NDPAnnouncement frame in step S109. For example, respective parameterscontained in the HE NDP Announcement frame are supplied from the accesscontrol unit 105.

The NDP notification frame is transmitted as a sounding request using anull data packet, and sounding using a null data packet is returned fromthe communication apparatus 11 having received the sounding request. Thereturned sounding is analyzed by the management information processingunit 114. As a result, a transmission parameter contained in a triggerframe is specified, for example.

In step S110, the management information generation unit 106 sets atransmission parameter of uplink multiuser MIMO and the like specifiedby the management information processing unit 114 to generate a triggerframe.

In step S111, the wireless transmission processing unit 109 transmitsthe trigger frame generated by the management information generationunit 106. Data multiplexed by multiuser MIMO is transmitted inaccordance with transmission timing designated by the transmissionparameter contained in the trigger frame transmitted here is transmittedfrom the communication apparatus 11 having received the trigger frame.

In step S112, the wireless reception processing unit 111 receives a dataframe transmitted from each of the communication apparatuses 11 byuplink multiuser MIMO to AC. This processing corresponds to theprocessing performed by AC at the time t4 in FIG. 16 . The data framereceived by the wireless reception processing unit 111 is supplied tothe reception data construction unit 115, and analyzed.

For example, Uplink Direct Data transmitted from Near Station and UplinkDirect Data transmitted from Far Station are temporarily stored in thereception buffer 116, and then output from the interface unit 101 to thedevice control unit 23 as reception data. In addition, Uplink Relay Datatransmitted from Far Station and addressed to IG is temporarily storedin the reception buffer 116, and then output to the transmission buffer102 via the interface unit 101 and stored as data to be transmitted byuplink multiuser MIMO to IG.

In step S113, the management information generation unit 106 transmitsan ACK frame to the communication apparatus 11 as a transmitter of areceived frame as necessary, and transmits an NACK frame to thecommunication apparatus 11 as a transmitter of a frame not received.

In a case of determination that the current timing is not timing forperforming uplink multiuser MIMO to AC in step S108, the processing fromsteps S109 to S113 is skipped.

In step S114, the access control unit 105 determines whether or not thetrigger frame transmitted from IG has been received. In a case where thetrigger frame transmitted from IG has been received, the trigger frameis analyzed at the management information processing unit 114.Thereafter, information associated with the transmission parameter issupplied to the access control unit 105. Note that a process forreceiving the NDP notification frame and returning a non-data frame maybe performed prior to reception of the trigger frame.

In a case of determination that the trigger frame transmitted from IGhas been received in step S114, the access control unit 105 acquires atransmission parameter used for uplink multiuser MIMO to IG on the basisof an analysis result obtained by the management information processingunit 114 in step S115.

In step S116, the access control unit 105 determines whether or not datato be transmitted to IG is present. Uplink Direct Data from AC itself toIG, and Uplink Relay Data transmitted from Far Station and addressed toIG are stored in the transmission buffer 102 as data to be transmittedto IG.

In a case of determination that data to be transmitted to IG is presentin S116, the transmission frame construction unit 104 reads and acquiresthe data to be transmitted to IG from the transmission buffer 102 instep S117.

In step S118, the wireless transmission processing unit 109 multiplexesUplink Direct Data and Uplink Relay Data, and transmits the multiplexeddata by uplink multiuser MIMO to IG. This processing corresponds to theprocessing performed by AC at the time t14 in FIG. 16 .

Timing of uplink multiuser MIMO to IG is controlled by the transmissiontiming control unit 107 on the basis of the transmission parameteracquired by the access control unit 105, for example.

In a case of determination that the trigger frame transmitted from IGhas not been received in step S114, the processing from steps S115 toS118 is skipped. Moreover, in a case of determination that transmissiondata is absent in step S116, processing in steps S117 and S118 isskipped.

In step S119, the access control unit 105 determines whether or not thecurrent timing is timing for performing downlink multiuser MIMO from AC.

In a case of determination that the current timing is timing forperforming downlink multiuser MIMO from AC in step S119, the accesscontrol unit 105 determines whether or not data to be transmitted ispresent in step S120. Downlink Direct Data from AC itself to NearStation, and Downlink Relay Data transmitted from IG and addressed toFar Station are stored in the transmission buffer 102 as data to betransmitted.

In a case of determination that data to be transmitted is present inS120, the transmission frame construction unit 104 reads and acquiresthe data to be transmitted from the transmission buffer 102 in stepS121.

In step S122, the wireless transmission processing unit 109 multiplexesDownlink Direct Data and Downlink Relay Data, and transmits themultiplexed data by downlink multiuser MIMO from AC. This processingcorresponds to the processing performed by AC at the time t21 in FIG. 16.

In a case of determination that the current timing is not timing forperforming downlink multiuser MIMO from AC in step S119, or in a casewhere data to be transmitted is absent in step S120, the process ends.In addition, in a case of determination of non-operation as AC in stepS102, the process similarly ends.

As described above, the wireless communication module 25 of AC functionsas a communication control unit which transmits a trigger frame ofuplink multiuser MIMO to AC, and receives data multiplexed andtransmitted from a plurality of the communication apparatuses 11 eachhaving received the trigger frame.

In addition, the wireless communication module 25 of AC functions as acommunication control unit which receives a trigger frame transmittedfrom IG as a frame of uplink multiuser MIMO to IG, and transmits, to IG,data multiplexed in accordance with a transmission parameter containedin the trigger frame.

Operation of IG

Processing performed by IG will be subsequently described with referenceto a flowchart in FIGS. 21 and 22 . Description similar to the abovedescription will be omitted where appropriate.

In step S131, the device control unit 23 of IG acquires own roleinformation.

In step S132, the device control unit 23 determines operation ornon-operation as IG.

In a case where operation as IG is determined in step S132, theinterface unit 101 determines whether or not downlink data has beensupplied in step S133.

For example, in a case where data transmitted from an external apparatusand addressed to Near Station is received by the Internet connectionmodule 21, the data addressed to Near Station is supplied from thedevice control unit 23 as downlink data. In addition, in a case wheredata transmitted from an external apparatus and addressed to Far Stationis received by the Internet connection module 21, the data addressed toFar Station is supplied from the device control unit 23 as downlinkdata.

In a case of determination that downlink data has been supplied in stepS133, the interface unit 101 determines whether or not the downlink datais data addressed to Far Station in step S134.

In a case of determination that the downlink data is data addressed toFar Station in step S134, the interface unit 101 outputs the datasupplied from the device control unit 23 to the transmission buffer 102,and causes the transmission buffer 102 to store the data as DownlinkRelay Data in step S135.

On the other hand, in a case of determination that the downlink data isnot data addressed to Far Station but data addressed to Near Station instep S134, the interface unit 101 outputs the data supplied from thedevice control unit 23 to the transmission buffer 102, and causes thetransmission buffer 102 to store the data as Downlink Direct Data instep S136.

After the data is stored in step S135 or step S136, or in a case ofdetermination that downlink data has not been supplied in step S133, theprocess proceeds to step S137.

In step S137, the access control unit 105 determines whether or not thecurrent timing is timing for performing uplink multiuser MIMO to IG.

In a case of determination that the current timing is timing forperforming uplink multiuser MIMO to IG in step S137, the managementinformation generation unit 106 generates an NDP notification frame, andcauses the wireless transmission processing unit 109 to transmit the NDPnotification frame in step S138.

The NDP notification frame is transmitted as a sounding request using anull data packet, and sounding using a null data packet is returned fromthe communication apparatus 11 having received the sounding request. Thereturned sounding is analyzed by the management information processingunit 114. As a result, a transmission parameter contained in a triggerframe is specified, for example.

In step S139, the management information generation unit 106 sets atransmission parameter and the like of uplink multiuser MIMO specifiedby the management information processing unit 114 to generate a triggerframe.

In step S140, the wireless transmission processing unit 109 transmitsthe trigger frame generated by the management information generationunit 106. Data multiplexed by multiuser MIMO is transmitted inaccordance with transmission timing designated by the transmissionparameter contained in the trigger frame transmitted here is transmittedfrom the communication apparatus 11 having received the trigger frame.

In step S141, the wireless reception processing unit 111 receives a dataframe transmitted from each of the communication apparatuses 11 byuplink multiuser MIMO to IG. This processing corresponds to theprocessing performed by IG at the time t14 in FIG. 16 . The data framereceived by the wireless reception processing unit 111 is supplied tothe reception data construction unit 115, and analyzed.

For example, Uplink Direct Data and Uplink Relay Data transmitted fromAC are temporarily stored in the reception buffer 116, and then outputfrom the interface unit 101 to the device control unit 23 as receptiondata.

In addition, Uplink Direct Data transmitted from Near Station istemporarily stored in the reception buffer 116 in a similar manner, andthen output from the interface unit 101 to the device control unit 23 asreception data.

In step S142, the management information generation unit 106 transmitsan ACK frame to the communication apparatus 11 as a transmitter of areceived frame as necessary, and transmits an NACK frame to thecommunication apparatus 11 as a transmitter of a frame not received.

In a case of determination that the current timing is not timing forperforming uplink multiuser MIMO to IG in step S137, the processing fromsteps S138 to S142 is skipped.

In step S143, the access control unit 105 determines whether or not thecurrent timing is timing for performing downlink multiuser MIMO from IG.

In a case of determination that the current timing is timing forperforming downlink multiuser MIMO from IG in step S143, the accesscontrol unit 105 determines whether or not data to be transmitted ispresent in step S144. Downlink Direct Data from IG itself to AC or NearStation is stored in the transmission buffer 102 as data to betransmitted.

In a case of determination that data to be transmitted is present inS144, the transmission frame construction unit 104 reads and acquiresthe data to be transmitted from the transmission buffer 102 in stepS145.

In step S146, the wireless transmission processing unit 109 multiplexesDownlink Direct Data, and transmits the multiplexed data by downlinkmultiuser MIMO from IG. This processing corresponds to the processingperformed by IG at the time t22 in FIG. 16 .

Note that Downlink Relay Data to Far Station may be transmitted bydownlink multiuser MIMO from IG. In this case, Downlink Direct Data toAC or Near Station, and Downlink Relay Data to Far Station aremultiplexed, and transmitted by downlink multiuser MIMO from IG.

In step S147, the access control unit 105 determines whether or not thetrigger frame transmitted from AC has been received. In a case ofdetermination that the trigger frame transmitted from AC has beenreceived, the trigger frame is analyzed at the management informationprocessing unit 114, and information associated with the transmissionparameter is supplied to the access control unit 105. Note that aprocess for receiving an NDP notification frame and returning a non-dataframe may be performed prior to reception of the trigger frame.

In a case of determination that the trigger frame transmitted from AChas been received in step S147, the access control unit 105 acquires atransmission parameter used for uplink multiuser MIMO to AC on the basisof an analysis result obtained by the management information processingunit 114 in step S148.

In step S149, the access control unit 105 determines whether or not datato be transmitted to AC is present. Downlink Direct Data from IG itselfto AC, and Downlink Relay Data transmitted from IG itself and addressedto Far Station are stored in the transmission buffer 102 as data to betransmitted to AC.

In a case of determination that data to be transmitted to IG is presentin S149, the transmission frame construction unit 104 reads and acquiresthe data to be transmitted to AC from the transmission buffer 102 instep S150.

In step S151, the wireless transmission processing unit 109 multiplexesDownlink Direct Data and Downlink Relay Data, and transmits themultiplexed data by uplink multiuser MIMO to AC. This processingcorresponds to the processing performed by IG at the time t4 in FIG. 16.

Timing of uplink multiuser MIMO to AC is controlled by the transmissiontiming control unit 107 on the basis of the transmission parameteracquired by the access control unit 105, for example.

In a case of determination that the trigger frame transmitted from AChas not been received in step S147, the processing from steps S148 toS151 is skipped. Thereafter, the process ends. Moreover, in a case ofdetermination that transmission data is absent in step S149, processingin steps S150 and S151 is skipped. Thereafter, the process ends. In acase of determination of non-operation as IG in step S132, the processsimilarly ends.

As described above, the wireless communication module 25 of IG functionsas a communication control unit which transmits a trigger frame ofuplink multiuser MIMO to IG, and receives data multiplexed andtransmitted from a plurality of the communication apparatuses 11 eachhaving received the trigger frame.

In addition, the wireless communication module 25 of IG functions as acommunication control unit which receives a trigger frame transmittedfrom AC as a frame of uplink multiuser MIMO to AC, and transmits, to AC,data multiplexed in accordance with a transmission parameter containedin the trigger frame.

Operation of Near Station

Processing performed by Near Station will be subsequently described withreference to a flowchart in FIG. 23 . Description similar to the abovedescription will be omitted where appropriate.

In step S161, the device control unit 23 of Near Station acquires ownrole information.

In step S162, the device control unit 23 determines operation ornon-operation as Near Station.

In a case of determination of operation as Near Station in step S162,the interface unit 101 determines whether or not uplink data has beensupplied in step S163. For example, in a case where the device controlunit 23 transmits data generated by an executed application to anotherapparatus, data to be transmitted is supplied from the device controlunit 23 as uplink data.

In a case of determination that the uplink data has been supplied instep S163, the interface unit 101 outputs the data supplied from thedevice control unit 23 to the transmission buffer 102, and causes thetransmission buffer 102 to store the data as Uplink Direct Data in stepS164. In a case of determination that the uplink data has not beensupplied in step S163, processing in step S164 is skipped.

In step S165, the access control unit 105 determines whether or not atrigger frame transmitted from AC has been received. In a case where thetrigger frame transmitted from AC has been received, the trigger frameis analyzed at the management information processing unit 114, andinformation associated with a transmission parameter is supplied to theaccess control unit 105. Note that a process for receiving an NDPnotification frame and returning a non-data frame may be performed priorto reception of the trigger frame.

In a case of determination that the trigger frame transmitted from AChas been received in step S165, the access control unit 105 acquires atransmission parameter used for uplink multiuser MIMO to AC on the basisof an analysis result obtained by the management information processingunit 114 in step S166.

In step S167, the access control unit 105 determines whether or not datato be transmitted to AC is present. Uplink Direct Data addressed fromNear Station itself to AC is stored in the transmission buffer 102 asdata to be transmitted to AC.

In a case of determination that data to be transmitted to AC is presentin S167, the transmission frame construction unit 104 reads and acquiresthe data to be transmitted to AC from the transmission buffer 102 instep S168.

In step S169, the wireless transmission processing unit 109 transmitsUplink Direct Data by uplink multiuser MIMO to AC. This processingcorresponds to the processing performed by Near Station at the time t4in FIG. 16 .

Timing of uplink multiuser MIMO to AC is controlled by the transmissiontiming control unit 107 on the basis of the transmission parameteracquired by the access control unit 105, for example.

In a case of determination that the trigger frame transmitted from AChas not been received in step S165, or in a case of determination thatdata to be transmitted to AC is absent in step S167, the processproceeds to step S170. In a case where data transfer is performed instep S169, the process similarly proceeds to step S170.

In step S170, the access control unit 105 determines whether or not thetrigger frame transmitted from IG has been received. In a case where thetrigger frame transmitted from IG has been received, the trigger frameis analyzed at the management information processing unit 114, andinformation associated with the transmission parameter is supplied tothe access control unit 105. Note that a process for receiving an NDPnotification frame and returning a non-data frame may be performed priorto reception of the trigger frame.

In a case of determination that the trigger frame transmitted from IGhas been received in step S170, the access control unit 105 acquires atransmission parameter used for uplink multiuser MIMO to IG on the basisof an analysis result obtained by the management information processingunit 114 in step S171.

In step S172, the access control unit 105 determines whether or not datato be transmitted to IG is present. Uplink Direct Data addressed fromNear Station itself to IG is stored in the transmission buffer 102 asdata to be transmitted to IG.

In a case of determination that data to be transmitted to IG is presentin S172, the transmission frame construction unit 104 reads and acquiresthe data to be transmitted to IG from the transmission buffer 102 instep S173.

In step S174, the wireless transmission processing unit 109 transmitsUplink Direct Data by uplink multiuser MIMO to IG. This processingcorresponds to the processing performed by Near Station at the time t14in FIG. 16 .

Timing of uplink multiuser MIMO to IG is controlled by the transmissiontiming control unit 107 on the basis of the transmission parameteracquired by the access control unit 105, for example.

In a case of determination that the trigger frame transmitted from IGhas not been received in step S170, or in a case of determination thatdata to be transmitted to IG is absent in step S172, the process ends.In a case of determination of non-operation as Near Station in stepS162, the process similarly ends.

As described above, the wireless communication module 25 of Near Stationfunctions as a communication control unit which receives a trigger frametransmitted from AC as a frame of uplink multiuser MIMO to AC, andtransmits data to AC in accordance with a transmission parametercontained in the trigger frame.

In addition, the wireless communication module 25 of Near Stationfunctions as a communication control unit which receives a trigger frametransmitted from IG as a frame of uplink multiuser MIMO to IG, andtransmits data to IG in accordance with a transmission parametercontained in the trigger frame.

Operation of Far Station

Processing performed by Far Station will be subsequently described withreference to a flowchart in FIG. 24 . Description similar to the abovedescription will be omitted where appropriate.

In step S181, the device control unit 23 of Far Station acquires ownrole information.

In step S182, the device control unit 23 determines operation ornon-operation as Far Station.

In a case where operation as Far Station is determined in step S182, theinterface unit 101 determines whether or not uplink data has beensupplied in step S183. For example, in a case where the device controlunit 23 transmits data generated by an executed application to anotherapparatus, data to be transmitted is supplied from the device controlunit 23 to the interface unit 101 as uplink data.

In a case of determination that uplink data has been supplied in stepS183, the interface unit 101 determines whether or not the uplink datais data addressed to IG in step S184.

In a case of determination that the uplink data is data addressed to IGin step S184, the interface unit 101 outputs data supplied from thedevice control unit 23 to the transmission buffer 102, and causes thetransmission buffer 102 to store the data as Uplink Relay Data in stepS185.

On the other hand, in a case of determination that the uplink data isdata addressed not to IG but to AC in step S184, the interface unit 101outputs data supplied from the device control unit 23 to thetransmission buffer 102, and causes the transmission buffer 102 to storethe data as Uplink Direct Data in step S186.

After the data is stored in step S185 or step S186, or in a case ofdetermination that uplink data has not been supplied in step S183, theprocess proceeds to step S187.

In step S187, the access control unit 105 determines whether or not thetrigger frame transmitted from AC has been received. In a case where thetrigger frame transmitted from AC has been received, the trigger frameis analyzed at the management information processing unit 114, andinformation associated with a transmission parameter is supplied to theaccess control unit 105. Note that a process for receiving an NDPnotification frame and returning a non-data frame may be performed priorto reception of the trigger frame.

In a case of determination that the trigger frame transmitted from AChas been received in step S187, the access control unit 105 acquires atransmission parameter used for uplink multiuser MIMO to AC on the basisof an analysis result obtained by the management information processingunit 114 in step S188.

In step S189, the access control unit 105 determines whether or not datato be transmitted to AC is present. Uplink Direct Data addressed fromFar Station itself to AC, and Uplink Relay Data addressed from FarStation itself to IG are stored in the transmission buffer 102 as datato be transmitted to AC.

In a case of determination that data to be transmitted to AC is presentin S189, the transmission frame construction unit 104 reads and acquiresthe data to be transmitted to AC from the transmission buffer 102 instep S190.

In step S191, the wireless transmission processing unit 109 multiplexesUplink Direct Data and Uplink Relay Data, and transmits the multiplexeddata by uplink multiuser MIMO to AC. This processing corresponds to theprocessing performed by Far Station at the time t4 in FIG. 16 .

Timing of uplink multiuser MIMO to AC is controlled by the transmissiontiming control unit 107 on the basis of the transmission parameteracquired by the access control unit 105, for example.

In a case of determination that the trigger frame transmitted from AChas not been received in step S187, or in a case of determination thatdata to be transmitted to AC is absent in step S189, the process ends.In a case of determination of non-operation as Near Station in stepS182, the process similarly ends.

As described above, the wireless communication module 25 of Far Stationfunctions as a communication control unit which receives a trigger frametransmitted from AC as a frame of uplink multiuser MIMO to AC, andtransmits multiplexed data to AC in accordance with a transmissionparameter contained in the trigger frame.

As described above, efficient use of a transfer path in a wireless LANis achievable by allowing data transfer using multiuser MIMO in responseto triggers from a plurality of the communication apparatuses.

In addition, the current mechanism of multiuser MIMO is applicable todata transfer performed by another communication apparatus by allowingdata transfer using multiuser MIMO without limitation to a particularcommunication apparatus for triggering the data transfer.

A communication apparatus present around AC or IG is capable ofefficiently transmitting data by receiving a trigger frame transmittedfrom AC or IG, and performing data transfer by multiuser MIMO.

By giving IG a function of transmitting a trigger frame which triggersdata transfer by multiuser MIMO, achievable is such control which allowsanother apparatus to perform data transfer by multiuser MIMO only in acase of high transmission efficient.

By giving the function of AC to the communication apparatus 11 locatednear the center of the range desired by the user, and optimizing radiowave transmission power in the overall network, the network forperforming data transfer by multiuser MIMO can be defined only in aminimum necessary range.

<Modifications>

Described above has been the case where the function of AC, the functionof IG, and the function of IC are distributed. However, the function ofAP may be further divided, and each of the divided functions may bedistributed to a larger number of the communication apparatuses 11.

In the network where the function of AP is shared by a plurality of thecommunication apparatuses 11 as described above, data transfer by OFDMAmay be performed instead of data transfer by multiuser MIMO.

Configuration Example of Computer

A series of processes described above may be executed by hardware or maybe executed by software. In a case where the series of processes areexecuted by software, a program constituting the software is installedfrom a program recording medium into a computer incorporated indedicated hardware, a general-purpose personal computer, or the like.

FIG. 25 is a block diagram depicting a configuration example of hardwareof a computer which executes the series of processes described aboveunder the program.

A CPU (Central Processing Unit) 1001, a ROM (Read Only Memory) 1002, anda RAM (Random Access Memory) 1003 are connected to each other via a bus1004.

An input/output interface 1005 is further connected to the bus 1004. Aninput unit 1006 including a keyboard, a mouse, and the like, and anoutput unit 1007 including a display, a speaker, and the like areconnected to the input/output interface 1005. In addition, a storageunit 1008 including a hard disk, a non-volatile memory, and the like, acommunication unit 1009 including a network interface and the like, anda drive 1010 driving a removable medium 1011 are connected to theinput/output interface 1005.

According to the computer configured as above, the CPU 1001 loads aprogram stored in the storage unit 1008 into the RAM 1003 via theinput/output interface 1005 and the bus 1004, and executes the loadedprogram to perform the series of processes described above, for example.

The program executed by the CPU 1001 is recorded in the removable medium1011, or provided via a wired or wireless transfer medium such as alocal area network, the Internet, and digital broadcasting, andinstalled into the storage unit 1008, for example.

Note that the program executed by the computer may be a program wherethe processes are performed in time series in the order described in thepresent description, or a program where the processes are performed inparallel or at necessary timing such as an occasion of a call.

In the present description, a system refers to an assembly of aplurality of constituent elements (apparatuses, modules (parts), and thelike). It does not matter whether or not all the constituent elementsare contained in an identical housing. Accordingly, a plurality ofapparatuses stored in different housings and connected to each other viaa network, and one apparatus storing a plurality of modules in onehousing are each referred to as a system.

Note that advantageous effects described in the present description arepresented only by way of example. Advantageous effects to be offered arenot limited to these advantageous effects, but may include otheradvantages effects.

Embodiments according to the present technology are not limited to theembodiment described above. Various modifications may be made withoutdeparting from the subject matters of the present technology.

For example, the present technology may be configured as cloud computingwhere one function is shared by a plurality of apparatuses and processedin cooperation with each other via a network.

Moreover, the respective steps described in the above flowcharts may beexecuted by one apparatus, or may be shared and executed by a pluralityof apparatuses.

Furthermore, in a case where one step contains a plurality of processes,the plurality of processes contained in the one step may be executed byone apparatus, or may be shared and executed by a plurality ofapparatuses.

Examples of Configuration Combination

The present technology may have following configurations.

(1)

A communication apparatus including:

a communication control unit that transmits a first trigger framecontaining a transmission parameter used for data transmission to aplurality of apparatuses belonging to a wireless LAN, and receives datamultiplexed and transmitted from the plurality of apparatuses havingreceived the first trigger frame in accordance with the transmissionparameter, and

h receives a second trigger frame transmitted from a predeterminedapparatus of the plurality of apparatuses, and transmits multiplexeddata to the predetermined apparatus in accordance with a transmissionparameter contained in the received second trigger frame.

(2)

The communication apparatus according to (1) described above, furtherincluding:

a management unit that manages information associated with apparatusesthat perform respective functions including a function of access controlassociated with access to the wireless LAN and including transmission ofa beacon frame, and a function of a gateway of the wireless LAN for anexternal network.

(3)

The communication apparatus according to (2) described above, in which,

in a case where performing the function of the access control by thecommunication apparatus is managed by the management unit,

the communication control unit receives data addressed to thecommunication apparatus, and multiplexed and transmitted from thepredetermined apparatus that operates as an apparatus performing thefunction of the gateway, and data addressed to a remote apparatuslocated out of a radio wave reach range of the predetermined apparatus.

(4)

The communication apparatus according to (3) described above, in which

the communication control unit further receives data addressed to thecommunication apparatus and transmitted from a near apparatus locatedwithin the radio wave reach range of the predetermined apparatus, anddata addressed to the communication apparatus and data addressed to thepredetermined apparatus both transmitted from the remote apparatus.

(5)

The communication apparatus according to (3) or (4) described above, inwhich the communication control unit multiplexes and transmits dataaddressed from the communication apparatus to the predeterminedapparatus, and data addressed to the predetermined apparatus andtransmitted from the remote apparatus in response to reception of thesecond trigger frame transmitted from the predetermined apparatus.

(6)

The communication apparatus according to (4) described above, in which

the communication control unit multiplexes and transmits data addressedfrom the communication apparatus to the near apparatus, and dataaddressed to the remote apparatus and transmitted from the predeterminedapparatus.

(7)

The communication apparatus according to any one of (3) to (6) describedabove, in which

the communication control unit controls radio wave transmission power ina communication allowable range with the predetermined apparatus.

(8)

The communication apparatus according to (2) described above, in which,

in a case where performing the function of the gateway by thecommunication apparatus is managed by the management unit,

the communication control unit receives data multiplexed and transmittedfrom the predetermined apparatus that operates as an apparatusperforming the function of the access control, the data addressed fromthe predetermined apparatus to the communication apparatus, and dataaddressed from a remote apparatus located out of a radio wave reachrange of the communication apparatus to the communication apparatus.

(9)

The communication apparatus according to (8) described above, in which

the communication control unit further receives data addressed to thecommunication apparatus and transmitted from a near apparatus locatedwithin the radio wave reach range of the communication apparatus.

(10)

The communication apparatus according to (9) described above, in which

the communication control unit multiplexes and transmits data addressedfrom the communication apparatus to the predetermined apparatus, anddata transmitted via the predetermined apparatus as a relay andaddressed to the remote apparatus in response to reception of thetrigger frame transmitted from the predetermined apparatus.

(11)

The communication apparatus according to (9) or (10) described above, inwhich

the communication control unit multiplexes and transmits data addressedfrom the communication apparatus to the predetermined apparatus, anddata addressed from the communication apparatus to the near apparatus.

(12)

The communication apparatus according to any one of (8) to (11)described above, in which

the communication control unit controls radio wave transmission power ina communication allowable range with the predetermined apparatus.

(13)

A communication apparatus including:

a communication control unit that

receives a trigger frame transmitted from a first apparatus thatperforms a function of access control associated with access to awireless LAN and including transmission of a beacon frame, the triggerframe containing a transmission parameter used for data transmission,and,

in accordance with the transmission parameter contained in the receivedtrigger frame, multiplexes and transmits data addressed to the firstapparatus, and data transmitted via the first apparatus as a relay, andaddressed to a second apparatus that performs a function of a gateway ofthe wireless LAN for an external network.

(14)

The communication apparatus according to (13) described above, in which

the communication control unit receives data addressed from the firstapparatus to the communication apparatus, and multiplexed andtransmitted from the first apparatus, and data addressed from the secondapparatus to the communication apparatus.

(15)

A communication system including:

a first communication apparatus that includes

a management unit that manages information indicating that a function ofaccess control associated with access to a wireless LAN and includingtransmission of a beacon frame is performed, and

a communication control unit that transmits a first trigger framecontaining a transmission parameter used for data transmission to aplurality of apparatuses belonging to the wireless LAN, and receivesdata multiplexed and transmitted from the plurality of apparatuseshaving received the first trigger frame in accordance with thetransmission parameter, and also receives a second trigger frametransmitted from a predetermined apparatus of the plurality ofapparatuses, and transmits multiplexed data to the predeterminedapparatus in accordance with the transmission parameter contained in thereceived second trigger frame; and

a second communication apparatus that is the predetermined apparatus andincludes

a management unit that manages information indicating that a function ofa gateway of the wireless LAN for an external network is performed, and

a communication control unit that transmits the second trigger frame tothe plurality of apparatuses, and receives data multiplexed andtransmitted from the plurality of apparatuses each having received thesecond trigger frame in accordance with the transmission parameter, andalso receives the first trigger frame transmitted from the firstcommunication apparatus of the plurality of apparatuses, and transmitsmultiplexed data to the first communication apparatus in accordance withthe transmission parameter contained in the received first triggerframe.

(16)

A communication apparatus including:

a communication control unit that

transmits data to a plurality of apparatuses belonging to a wireless LANas multiplexed downlink data, and

receives multiplexed downlink data transmitted to a plurality ofcommunication apparatuses located around the communication apparatus,and extracts data addressed to the communication apparatus from thereceived data.

REFERENCE SIGNS LIST

-   -   11 Communication apparatus, 21 Internet connection module, 22        Information input module, 23 Device control unit, 24 Information        output module, 25 Wireless communication module, 51 Input/output        unit, 52 Communication control unit, 53 Baseband processing        unit, 101 Interface unit, 102 Transmission buffer, 103 Network        management unit, 104 Transmission frame construction unit, 105        Access control unit, 106 Management information generation unit,        107 Transmission timing control unit, 108 Transmission power        control unit, 109 Wireless transmission processing unit, 110        Antenna control unit, 111 Wireless reception processing unit,        112 Detection threshold control unit, 113 Reception timing        control unit, 114 Management information processing unit, 115        Reception data construction unit, 116 Reception buffer

The invention claimed is:
 1. A communication apparatus, comprising: acommunication control unit configured to: transmit a first trigger frameto a plurality of apparatuses associated with a wireless LAN, whereinthe first trigger frame includes a first transmission parameter for datatransmission, receive first multiplexed data from the plurality ofapparatuses based on the transmission parameter, receive a secondtrigger frame from a specific apparatus of the plurality of apparatuses,and transmit second multiplexed data to the specific apparatus based ona second transmission parameter contained in the received second triggerframe; and a management unit configured to manage information associatedwith the plurality of apparatuses that has functions including: afunction of access control associated with access to the wireless LANand including transmission of a beacon frame to each of the plurality ofapparatuses, wherein the beacon frame includes role separate informationindicating roles performed by each of the plurality of apparatusesbelonging to the wireless LAN, and a function of a gateway of thewireless LAN for an external network.
 2. The communication apparatusaccording to claim 1, wherein the communication apparatus has thefunction of the access control, the management unit is furtherconfigured to manage the function of the access control, thecommunication control unit is further configured to receive the firstmultiplexed data from the specific apparatus that has the function ofthe gateway, and the first multiplexed data includes: first dataaddressed to the communication apparatus, and second data addressed to aremote apparatus located out of a radio wave reach range of the specificapparatus.
 3. The communication apparatus according to claim 2, whereinthe communication control unit is further configured to: receive thirddata addressed to the communication apparatus and transmitted from anear apparatus located within the radio wave reach range of the specificapparatus, and receive fourth data addressed to the communicationapparatus and fifth data addressed to the specific apparatus, whereinthe fourth data and the fifth data are transmitted from the remoteapparatus.
 4. The communication apparatus according to claim 2, whereinthe communication control unit is further configured to multiplex andtransmit, third data and fourth data as the second multiplexed data, inresponse to reception of the second trigger frame from the specificapparatus, wherein the third data is addressed from the communicationapparatus to the specific apparatus, and the fourth data is addressed tothe specific apparatus and transmitted from the remote apparatus.
 5. Thecommunication apparatus according to claim 3, wherein the communicationcontrol unit is further configured to multiplex and transmit: fifth dataaddressed from the communication apparatus to the near apparatus, andsixth data addressed to the remote apparatus and transmitted from thespecific apparatus.
 6. The communication apparatus according to claim 2,wherein the communication control unit is further configured to controlradio wave transmission power in a communication allowable range withthe specific apparatus.
 7. The communication apparatus according toclaim 1, wherein the communication apparatus has the function of thegateway, the management unit is further configured to manage thefunction of the gateway, the communication control unit is furtherconfigured to receive the first multiplexed from the specific apparatusthat has the function of the access control, and the first multiplexeddata includes: first data addressed from the specific apparatus to thecommunication apparatus, and second data addressed to the communicationapparatus from a remote apparatus located out of a radio wave reachrange of the communication apparatus.
 8. The communication apparatusaccording to claim 7, wherein the communication control unit is furtherconfigured to receive third data addressed to the communicationapparatus and transmitted from a near apparatus located within the radiowave reach range of the communication apparatus.
 9. The communicationapparatus according to claim 8, wherein the communication control unitis further configured to multiplex and transmit, fourth data and fifthdata, in response to reception of the second trigger frame from thespecific apparatus, wherein the fourth data is addressed from thecommunication apparatus to the specific apparatus, and the fifth datatransmitted via the specific apparatus as a relay and addressed to theremote apparatus from the communication apparatus.
 10. The communicationapparatus according to claim 8, wherein the communication control unitis further configured to multiplex and transmit: fourth data addressedfrom the communication apparatus to the predetermined specificapparatus, and fifth data addressed from the communication apparatus tothe near apparatus.
 11. The communication apparatus according to claim7, wherein the communication control unit is further configured tocontrol radio wave transmission power in a communication allowable rangewith the specific apparatus.
 12. A communication apparatus, comprising:a communication control unit configured to: receive a trigger frame froma first apparatus, wherein the first apparatus has a function of accesscontrol associated with access to a wireless LAN and transmission of abeacon frame to a plurality of apparatuses associated with the wirelessLAN, the beacon frame includes role separate information indicatingroles performed by each of the plurality of apparatuses belonging to thewireless LAN, and the trigger frame includes a transmission parameterused for data transmission, and multiplex and transmit, first dataaddressed to the first apparatus and second data addressed to a secondapparatus, based on the transmission parameter included in the triggerframe, wherein the second data is transmitted via the first apparatus asa relay, and the second apparatus has a function of a gateway of thewireless LAN for an external network.
 13. The communication apparatusaccording to claim 12, wherein the communication control unit is furtherconfigured to receive: third data addressed from the first apparatus tothe communication apparatus and multiplexed and transmitted from thefirst apparatus, and fourth data addressed from the second apparatus tothe communication apparatus.
 14. A communication system, comprising: afirst communication apparatus that includes: a first management unitconfigured to manage information indicating that the first communicationapparatus has a function of access control associated with access to awireless LAN, wherein the function of the access control includestransmission of a beacon frame, and a first communication control unitconfigured to: transmit a first trigger frame to a plurality ofapparatuses belonging to the wireless LAN, wherein the first triggerframe includes a first transmission parameter for data transmission,receive first multiplexed data from the plurality of apparatuses basedon the first transmission parameter, receive a second trigger frame froma specific apparatus of the plurality of apparatuses, and transmitsecond multiplexed data to the specific apparatus based on a secondtransmission parameter contained in the received second trigger frame;and a second communication apparatus that is the specific apparatus andincludes: a second management unit configured to manage informationindicating that the second communication apparatus has a function of agateway of the wireless LAN for an external network, and a secondcommunication control unit configured to: transmit the second triggerframe to the plurality of apparatuses, receive third multiplexed datafrom the plurality of apparatuses based on the second transmissionparameter, receive the first trigger frame transmitted from the firstcommunication apparatus of the plurality of apparatuses, and transmitfourth multiplexed data to the first communication apparatus based onthe first transmission parameter included in the received first triggerframe.
 15. A communication apparatus, comprising: a communicationcontrol unit configured to: transmit first multiplexed downlink data toa plurality of apparatuses belonging to a wireless LAN, receive secondmultiplexed downlink data from a first apparatus of the plurality ofapparatuses, and extract the first data addressed to the communicationapparatus from the second multiplexed downlink data; and a managementunit configured to manage information associated with the plurality ofapparatuses that has functions including: a function of access controlassociated with access to the wireless LAN and including transmission ofa beacon frame to each of the plurality of apparatuses, wherein thebeacon frame includes role separate information indicating rolesperformed by each of the plurality of apparatuses belonging to thewireless LAN, and a function of a gateway of the wireless LAN for anexternal network.